What causes histamine allergies
The immune system protects the body by producing specialised proteins called antibodies.
Antibodies identify potential threats to your body, such as bacteria and viruses. They signal your immune system to release chemicals to kill the threat and prevent the spread of infection.
In the most common type of food allergy, an antibody known as immunoglobulin E (IgE) mistakenly targets a certain protein found in food as a threat. IgE can cause several chemicals to be released, the most significant being histamine.
Histamine causes most of the typical symptoms that happen during an allergic reaction.
For example, histamine:
- causes little blood vessels to expand and the surrounding skin to become red and swell up
- affects nerves in the skin, causing itchiness
- increases the quantity of mucus produced in your nose lining, which causes itching and a burning sensation
In most food allergies, the release of histamine is limited to certain parts of the body, such as your mouth, throat or skin.
In anaphylaxis, the immune system goes into overdrive and releases large amounts of histamine and numerous other chemicals into your blood. This causes the wide range of symptoms associated with anaphylaxis.
It’s rare for someone to have an allergic reaction to food additives.
However, certain additives may cause a flare-up of symptoms in people with pre-existing conditions.
Sulphur dioxide (E220) and other sulphites (from numbers E221 to E228) are used as preservatives in a wide range of foods, especially soft drinks, sausages, burgers, and dried fruits and vegetables.
Sulphur dioxide is produced naturally when wine and beer are made, and is sometimes added to wine. Anyone who has asthma or allergic rhinitis may react to inhaling sulphur dioxide.
A few people with asthma own had an attack after drinking acidic drinks containing sulphites, but this isn’t thought to be extremely common.
Food labelling rules require pre-packed food sold in the UK, and the relax of the European Union, to show clearly on the label if it contains sulphur dioxide or sulphites at levels above 10mg per kg or per litre.
Benzoic acid (E210) and other benzoates (E211 to E215, E218 and E219) are used as food preservatives to prevent yeasts and moulds growing, most commonly in soft drinks. They happen naturally in fruit and honey.
Benzoates could make the symptoms of asthma and eczema worse in children who already own these conditions.
Sheet final reviewed: 15 April 2019
Next review due: 15 April 2022
Histamine: Friend or Foe? …or Frenemy?
From NIH MedlinePlus the Magazine
Histamine: is it the most annoying chemical in the body?
[Histamine molecule] “Bleh”
It’s the stuff that allergies are made of.
Hay fever? Food allergy? Skin allergies? Histamine plays a large role in every of them.
And those conditions frolic a large role in us. In 2015, CDC data showed that more than 8% of US adults had hay fever. More than 5% of US children had food allergies. And at least 12% of every US kids had skin allergies!
So what’s the deal? Why do we own such a pesky chemical in our body?
Well, histamine is generally our friend.
Histamine is a signaling molecule, sending messages between cells. It tells stomach cells to make stomach acid. And it helps our brain stay awake. You may own seen these effects illustrated by medicines that block histamine. Some antihistamines can make us sleepy and other antihistamines are used to treat acid reflux.
Histamine also works with our immune system.
It helps protect us from foreign invaders. When the immune system discovers an invader, immune cells called B-cells make IgE antibodies. The IgE’s are love “WANTED” signs that spread throughout the body, telling other immune cells about specific invaders to glance for.
Eventually mast cells and basophils pick up the IgE’s and become sensitized. When they come in contact with a target invader…They spew histamine and other inflammatory chemicals.
Blood vessels become leakier, so that white blood cells and other protective substances can sneak through and fight the invader.
Histamine’s actions are grand for protecting the body against parasites.
But with allergies, the immune system overreacts to harmless substances, not parasites.
This is when histamine becomes our foe. Common allergens include peanuts, pollen, and animal dander.
Leaky vessels cause tearing in eyes, congestion in the nose, and swelling…basically anywhere. Histamine works with nerves to produce itching. In food allergies it can cause vomiting and diarrhea. And it constricts muscles in the lungs, making it harder to breathe.
Most worrisome is when histamine causes anaphylaxis, a severe reaction that is potentially fatal.
Swollen airways can prevent breathing, and a rapid drop in blood pressure could starve organs of vital blood.
So what can be done about histamine?
Antihistamines block cells from seeing histamine and can treat common allergies. Medicines love steroids can calm the inflammatory effects of allergies. And anaphylaxis needs to be treated with a shot of epinephrine, which opens up airways, and increases blood pressure.
So our relationship with histamine is…complicated. We can do better.
NIH and specifically the National Institute of Allergy and Infectious Diseases (NIAID) support research of histamine and its related conditions.
Grand progress is being made in understanding allergy triggers and managing allergic symptoms, and figuring out why histamine, our frenemy, acts the way it does.
Find out specific up-to-date research and stories from medlineplus.gov and NIH MedlinePlus the magazine, medlineplus.gov/magazine/, and study more about NIAID research at niaid.nih.gov.
Sniffling, sneezing and struggling through allergy season this year?
You may desire to lay off alcohol for a while. Studies own found that alcohol can cause or worsen the common symptoms of asthma and hay fever, love sneezing, itching, headaches and coughing.
But the problem is not always the alcohol itself.
Beer, wine and liquor contain histamine, produced by yeast and bacteria during the fermentation process. Histamine, of course, is the chemical that sets off allergy symptoms.
Wine and beer also contain sulfites, another group of compounds known to provoke asthma and other allergy-like symptoms.
In one study in Sweden in 2005, scientists looked at thousands of people and found that compared with the general population, those with diagnoses of asthma, bronchitis and hay fever were far more likely to experience sneezing, a runny nose and “lower-airway symptoms” after having a drink. Red wine and white wine were the most frequent triggers, and women, for unknown reasons, were about twice as likely to be affected as men.
If you discover your body reacts to a diverse group of foods — tell, spinach, tomatoes, wine, and sauerkraut — with symptoms that range from a stuffy nose to migraine headaches, you may not be allergic to those foods.
Instead, you may own what's called histamine intolerance, since every those foods own high levels of histamine in them.
Histamine is a chemical our bodies produce naturally, and it's also found in certain foods. In situations involving "true" allergies, your body releases histamine, and that histamine, in turn, provokes the response we ponder of as an allergic reaction.
Histamine intolerance isn't a true allergic reaction. Instead, it refers to a reaction some people experience to foods that own high levels of naturally occurring histamine.
People with histamine intolerance often own low levels of either of two extremely specific enzymes—diamine oxidase (DAO) and histamine-N-methyltransferase (HNMT) — that process histamine in your body.
Without enough of those enzymes to process the histamine, it can build up over time and cause symptoms throughout the body.
Non-IgE-mediated food allergy
There’s another type of food allergy known as a non-IgE-mediated food allergy, caused by diverse cells in the immune system.
This is much harder to diagnose as there’s no test to accurately confirm non-IgE-mediated food allergy.
This type of reaction is largely confined to the skin and digestive system, causing symptoms such as heartburn, indigestion and eczema.
In babies, a non-IgE-mediated food allergy can also cause diarrhoea and reflux, where stomach acid leaks up into the throat.
Who’s at risk?
Exactly what causes the immune system to error harmless proteins as a threat is unclear but some things are thought to increase your risk of a food allergy.
If you own a parent, brother or sister with an allergic condition – such as asthma, eczema or a food allergy – you own a slightly higher risk of developing a food allergy.
However, you may not develop the same food allergy as your family members.
Other allergic conditions
Children who have atopic dermatitis (eczema) in early life are more likely to develop a food allergy.
In children, the foods that most commonly cause an allergic reaction are:
- milk – if a kid has an allergy to cows’ milk, they’re probably allergic to every types of milk, as well as infants’ and follow-on formula
In adults, the foods that most commonly cause an allergic reaction are:
- tree nuts – such as walnuts, brazil nuts, almonds and pistachios
- shellfish – such as crab, lobster and prawns
However, any type of food can potentially cause an allergy.
Some people own allergic reactions to:
- celery or celeriac – this can sometimes cause anaphylactic shock
- pine nuts (a type of seed)
- sesame seeds
- fruit and vegetables – these generally only cause symptoms affecting the mouth, lips and throat (oral allergy syndrome)
- gluten – a type of protein found in cereals
- meat – some people are allergic to just one type of meat, while others are allergic to a range of meats; a common symptom is skin irritation
The rise in food allergy cases
The number of people with food allergies has risen sharply over the past few decades and, although the reason is unclear, other allergic conditions such as atopic dermatitis own also increased.
One theory behind the rise is that a typical child’s diet has changed considerably over the final 30 to 40 years.
Another theory is that children are increasingly growing up in «germ-free» environments.
This means their immune systems may not get sufficient early exposure to the germs needed to develop properly.
This is known as the hygiene hypothesis.